On paper, Harvin presents a unique challenge for the Broncos' defense. They don't have a lot of film to see how the Seahawks plan to use him. And Harvin could test the depth of the Denver secondary, especially in the middle of the field where they are missing cornerback Chris Harris.

Then again, Harvin has always looked good on paper. His biggest challenge has been staying on the field.

UPDATE: The Seahawks confirmed to NFL Media on Thursday that Harvin passed concussion protocol and has been cleared to play in Super Bowl XLVIII.